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(No Model.) 2 Sheets-Sheet 1. W. E. WHEELER.

. ELEOTRIGALLY OPERATED DENTAL ENGINE.

No. 584,536. Patented Feb. 19,1895.

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(No Model.) 2 SheetsSheet 2. W. E. WHEELER.

ELEGTRIGALLY OPERATED DENTAL ENGINE.

No. 534,536. Patented Feb. 19,1895.

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UNITED STATES PATENT OFFICE.

WILLIAM EUGENE WVHEELER, OF DAYTON, TENNESSEE, ASSIGNOR OF ONE- IIALF TOGEORGE W. JOHNSON AND JAMES F. JOHNSON, OF SAME PLACE.

ELECTRICALLY-OPERATED DENTAL ENGINE.

SIPEOIFIGATION forming part of Letters Patent No. 534,536, datedFebruary 19, 1895.

Application filed October 6, l 893- To all whom it may concern.-

Be it known that I, WILLIAM EUGENE WHEELER, residing at Dayton, in thecounty of Rhea and State of Tennessee, have id vented a new and usefulElectric Dental Engine, of which the following is a specification.

My invention relates to improvements in dental engines, and it hasprimarily for its object to provide a simple and convenient IOelectrically operated engine of this character which can be easilymanipulated and which willserve to materiallylessen the labor of thedental operator. 1

Furthermore it has for its object to provide a dental engine soconstructed and arranged that the operator can at all times stand onboth feet and work from each side of the chair, thereby enabling theoperator to perform such operation quicker, and with more freedom, andease of movement, and in consequence mitigating the pain of the patient.

It also has for its object to provide an engine of this kind havingsuitably arranged and easily operated shifting devices whereby the speedof the drill-operating drive-wheel can be increased or decreased asdesired, and the motor stopped when the drill-holding cable is hung upat rest.

With other minor objects in view which hereinafter will appear, myinvention consists in such novel features of construction and peculiarcombination of parts as will be first described in detail and then bespecifically pointed out in the appended claims, reference 5 being hadto the accompanying drawings, in

which- Figure 1 is a perspective view of my improved dental engineshowing the same in its operative position on the bracket table. Fig.

2 is a top plan view of the engine or motor. Fig. 3 is a longitudinalsection thereof taken practically on the line 8-3 in Fig. 2, and Fig. 4is a partial end elevation taken from the automatic switch end.

In its practical construction my invention embodies an electric motor,having field magnets, and in which the armature runs verticallyor in aperpendicular position, the shaft of which has a friction disk which isadapted to engage and drive the drill-operating devices.

Serial No. 487,388- (No model.)

In my arrangement of the motor the field magnets are so arranged as toplace the armature shaft and armature in a perpendicular position, so asto make it practical and convenient to use the shifting devices attachedthereto in the manner hereinafter described.

Referring now to the accompanying drawings by letters of reference A Aindicate the field magnets; B B, their coils; O, the armature; D D, thebrushes; E E, the armature supports, which parts constitute the motor,and are supported and held in position, in practice on the bracket tableF, although they may be, if desired, secured upon a suitable baseprovided therefor.

The armature O as before stated runs vertical, and has its shaft Gformed cone shaped at the lowerend and fitted in a cone bearing, whilethe upper end is fitted in and projects above the upper support E andhas detachably secured thereon a plane face wheel H slightly dished inthe center as shown at 7L.

At the front side of the motor or engine is secured a socket-likebracket 1, which is held insulated from the motor body by the rubberwashers t' i. In this socket is fitted to turn the vertical stemj of astandard J, to the upper end of which is connected a horizontallydisposed arm K, which is normally held spring pressed in a downwarddirection by the spring 7c, and such arm has bifurcated members L Lwhich have journal boxes to receive the drilloperating spindle M, onwhich is mounted to turn therewith the friction wheel N, which has arubber rim N and which is disposed at right angles to the drive-wheel Hand normally held in contact therewith by the spring pressure beforementioned. One of the fric- 0 tion wheel bearing arms (L) is extendedand has a downwardly bent angular portion L which is arranged to engagea notched segmental support O, as shown most clearly in Figs. 1 and 3.

The bearing arm K has at one side a threaded extension 70* on which isadapted to be fitted the internally threaded sleeve 1', to which issecured the cable or sheath S.

On the inner end of the motor is secured too what I term the automaticswitch and cable rest, which comprises a pair of spring clasp- :2 sceneslike arms T T, which have secured thereto the terminals and of thecircuit wire IV, and such arms are normally spring pressed toward eachother, whereby to cause the terminals and to contact and thereby closethe circuit. An ordinary switch S is also preferably arranged in thecircuit wire as shown.

From the foregoing description taken in connection with the accompanyingdrawings the operation of my improved dental engine is best explained asfollows: When not in use the drill or handle end of the cable is fittedin and supported on the rest T, and as the diameter of the cable in thepractical construction of the parts is greater than the normal widthbetween the arms T T, such arms are caused to spread, and inconsequence, separate the terminals and break the circuit and stop themotor. \Vhen however the cable is lifted out of the rest for use, theterminals contact, close the circuit and set the motor in operation. Nowby shifting the wheel N, toward the periphery of the wheel II at oneside, the speed thereof is increased, and by shifting it toward the axisof the said wheel II the speed is proportionately decreased, the sameresults of speed being obtained for the wheel N if moved overonto theopposite side of the wheel I-Iit being understood the rotation of thewheel N then being in a reverse direction. Should the wheel N be heldcentrally over the dished portion of the wheel H, it is manifest thesame will be held from frictional contact therewith, and such wheel N bethen stopped from revolving.

It will be readily seen from 'the drawings that the drill-drivingdevices proper are so insulated from the motor or engine, as to preventany electrical contact or connection with either the operator orpatient, thereby preventing any possibility of a shock, and therebyrendering the machine perfectly safe.

It will also be manifest that by combining the drill shaft and the drivedisk thereon, with tension means for holding the disk against the motordrive wheel, the force ofcontact of the drill shaft disk against thedrive shaft disk may be so regulated that in case of accident, (the burrof drill getting caught in the mouth) the friction disk will slip andthus hold the drill from a too forcible rotation.

What I claim, and desire to secure by Letters Patent, is

1. An improved dental en ine comprising a motor having a friction drivewheel on its operating shaft, a movable drill shaft having a disk memberadapted to be rotated by contact with the aforesaid drive wheel, andmeans for adjusting the pressure of the said shaft toward the said drivewheel, whereby the said disk will become non-rotatable, when the drillmeets with a resistance greater than the contact tension of theaforesaid disk against the drive wheel as hereinbefore described.

2. An electric dental engine comprising a motor having a friction drivewheel on its armature shaft, a supporting member pivotally supported onthe motor frame to swing laterally over the drive wheel, and springpressed toward the said wheel, a drill shaft journaled in the saidmember and a friction disk fixedly held on the said shaft and in contactwith the drive wheel by the spring pressure of the supporting member,substantially as shown and described.

3. An electric dental engine comprising a main frame adapted to besecured to a bracket or table, and having field magnets secured thereto,an armature journaled on the frame and held to rotate vertically betweenthe said magnets said armature havinga friction drive wheel, a drilloperating disk held to engage the said drive wheel, the drill cableconnected with the bearing for the said disk and a combined automaticswitch member and rest for the drill end of the cable, arrangedsubstantially as shown whereby the engine will be stopped and started asthe cable is placed between and withdrawn from the said rest portion asset forth.

l. In an electric motive power dental engine, a rest for the cable,comprising yielding arms having the terminals of the circuit connectednormally held with their terminals in contact and to break such contact.when the cable is held thereon as specified.

5. In an electric motive power dental engine, a combined automaticswitch and cable rest, the switch being governed by the insertion andwithdrawal of the cable, to stop and start the engine substantially asdescribed.

6. An improved dental engine comprising an electric motor having africtional drive wheel or disk, a drill shaft having a'friction drivedisk, a pivoted supporting member for such shaft, and tension means forholding the drill shaft drive disk in frictional contact with thearmature shaft drive disk substaa tially as and for the purposesdescribed.

7. In combination with the motor and the armature friction wheel, .of alaterally swinging arm, a notched guide therefor, the drill shaftjournaled on the said arm, and a friction wheel mounted on the drillshaft to turn therewith held in contact with the face of the armaturefriction wheel all substantially as shown and for the purposesdescribed.

8. The combination with the motor, the armature shaft of which has afriction wheel having a plane face, of an insulated arm held on themotor to swing laterally over the said friction wheel, said arm beingheld spring pressed toward such Wheel, the drill-shaft journaled in thesaid arm, and a friction wheel on such shaft having a rubber rim, saidwheel being held in contact with the armature friction wheelsubstantially as shown and for the purposes specified.

IVILLIAM EUGENE "WHEELER.

IVitnesses:

H. B. RIvEs, THOMAS F. AUNSPAUGH.

